Carlowrightia torreyana

Torrey's wrightwort displays these distinguishing features:

The growth form ranges between that of an herb and a woody shrub; it is a perennial with a woody base and non-woody upper stems, which can grow along the ground or bend upward to about 0.5 m (1 ft 8 in) tall. Leaves with petioles arise opposite one another with blades which are broadly egg-shaped to round, and up 40 mm (1+5⁄8 in) long, though usually about half that. The calyx has 5 lobes, or (sepals), not 4. The white corollas, only 7–9 mm (1⁄4–3⁄8 in) long, are noticeably divided into upper and lower lips, with the lower lips prominently 3-lobed; on the upper lip there's a yellow "eye" fringed with maroon. Flowers have 2 stamens, not four, and grow closer to the corolla's lower lip than the upper. Small bracts, or bractlets, below each flower are not fused along one side from the base to the apex. It produces capsular-type fruits which are 8–12 mm (3⁄8–1⁄2 in) long.

In the USA, Torrey's wrightwort occurs in southwestern Texas. In Mexico, it is found in the north-central and northeastern states of Chihuahua, Sonora, Coahuila and Nuevo León.

The genus name Carlowrightia is named for Charles (Carlos) Wright, a botanist of the USA. The species name honors US botanist John Torrey. Torrey earlier had named the taxon Schaueria parvifolia, which in 1965 was reassigned by Dieter Carl Wasshausen to the genus Carlowrightia as Carlowrightia torreyana.

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